﻿/*******************************************************************************************
 * Copyright (c) 2009 Alex Robson, Rob Simmons, Craig Israel, and Rachel Twyford
 *
 * Use of this software in any form requires that you have both 
 * read and agreed to the following terms:
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the "Software"), 
 * to deal in the Software without restriction, including without limitation 
 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions: 
 *
 * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 * Redistributions in binary form must reproduce the above copyright notice, 
 * this list of conditions and the following disclaimer in the 
 * documentation and/or other materials provided with the distribution.
 * Neither the name of Nvigorate nor the names of its contributors may 
 * be used to endorse or promote products derived from this software without 
 * specific prior written permission. 
 *
 * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 
 * DISCLAIMED. IN NO EVENT SHALL ANY CONTRIBUTOR BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml.Linq;
using Nvigorate.Data.Query;
using Nvigorate.Relational.Mapping.Interface;
using Nvigorate.Xml;

namespace Nvigorate.Relational.Mapping
{
    [Serializable]
    public abstract class BaseJoin : IJoin, IEquatable<BaseJoin>
    {
        #region Implementation of IJoin

        protected string _subject;

        protected string _relative;

        protected SearchCriteria _joinCriteria;

        /// <summary>
        /// The root/parent record
        /// </summary>
        public string Subject
        {
            get { return _subject; }
            set { _subject = value; }
        }

        /// <summary>
        /// The child/relative record
        /// </summary>
        public string Relative
        {
            get { return _relative; }
            set { _relative = value; }
        }

        /// <summary>
        /// The criteria explaining how to associate the records
        /// </summary>
        public SearchCriteria JoinCriteria
        {
            get { return _joinCriteria; }
            set { _joinCriteria = value; }
        }

        #endregion

        public XElement GetXElementRepresentation()
        {
            return new XElement(
                "relates",
                new XAttribute("to", _subject),
                _joinCriteria.GetXElementRepresentation()
                );
        }

        public object ParseXElement(XElement element)
        {
            _subject = element.GetAttributeValue("to");
            _relative = element.Parent.GetAttributeValue("name");
            _joinCriteria = new SearchCriteria();
            _joinCriteria.ParseXElement(element.Descendants("criteria").First());
            return this;
        }

        #region Equality Members

        public bool Equals(BaseJoin obj)
        {
            if (ReferenceEquals(null, obj)) return false;
            if (ReferenceEquals(this, obj)) return true;
            return Equals(obj._subject, _subject) && Equals(obj._relative, _relative) && Equals(obj._joinCriteria, _joinCriteria);
        }

        public override bool Equals(object obj)
        {
            if (ReferenceEquals(null, obj)) return false;
            if (ReferenceEquals(this, obj)) return true;
            if (obj.GetType() != typeof (BaseJoin)) return false;
            return Equals((BaseJoin) obj);
        }

        public override int GetHashCode()
        {
            unchecked
            {
                int result = (_subject != null ? _subject.GetHashCode() : 0);
                result = (result*397) ^ (_relative != null ? _relative.GetHashCode() : 0);
                result = (result*397) ^ (_joinCriteria != null ? _joinCriteria.GetHashCode() : 0);
                return result;
            }
        }

        #endregion
    }
}